1. Field of the Invention
The present invention relates to an apparatus for rebuilding a worn track shoe for a line of track chain usable for a construction machine or the like and more particularly to improvement of or relating to an apparatus for rebuilding a worn shoe by a welding operation, werein an assembly of a shoe and a replacement lug is caused to turn upside down after completion of a welding operation over one welding area while they are brought in firm contact with one another.
2. Description of the Prior Art
As is well known, a shoe mounted on a line of track chain for a construction machine such as bulldozer or the like has a grouser projected outwardly of the surface and the grouser tends to wear increasingly as the construction machine continues to operate. Once the grouser has worn, a high intensity of tracting force fails to be generated due to reduced depth of driving of the grouser into the ground, resulting in decreased capability of excavating and degraded operational efficiency. For these reasons worn shoes should be repaired or rebuilt when the extent of wearing reaches a predetermined level during running operation. Rebuilding of a worn shoe is usually carried out by way of the steps of cutting off the worn part of grouser, fitting a replacement lug having a certain height to the latter and then butt welding an assembly of replacement lug and grouser along the welding area. Due to the necessity for welding operations on both the sides of the assembly, the latter is required to turn upside down after completion of the welding operation over the welding area on the one side. To carry out rebuilding of a worn shoe, the conventional apparatus is generally operated such that after welding on the one side of the assembly, the assembly is removed from the fitting jig, it is then turned upside down and finally it is mounted on the jig again. This leads to lower operational efficiency.
Prior to the welding operation the worn part of the grouser is usually cut off by means of a gas cutter and the shoe is gradually deformed during the cutting operation under the influence of heat at an elevated temperature. To eliminate deformation, the rebuilt shoe is hitherto straightened with the aid of a gate type press or the like and thereafter it is subjected to welding. However, it has been found that the rebuilt shoe resumes the original deformed state during the welding operation or before it is assembled with a line of track chain. For this reason a repaired shoe fails to be correctly fitted to track chain, causing an occurrence of loosening of tightened bolts, disconnection of the shoe from the track chain or the like malfunction.